Patent Document 1 (JP 2011-210480A) discloses a bus bar attached to a battery with a cathode for which aluminum is used and an anode for which copper is used. With this bus bar, a cathode connection portion composed of aluminum and an anode connection portion composed of copper are integrally coupled through metallic bonding.
The above-described cathode and anode have bolt shapes with outer circumferential surfaces provided with screw threads. Insertion holes into which the cathode and the anode are to be inserted are formed on the bus bar. By screwing nuts on the cathode and the anode with the cathode and the anode inserted in the insertion holes of the bus bar, the bus bar is electrically connected to the cathode and the anode.
Also, Patent Document 2 (JP 2013-16382A) discloses a configuration in which a detection terminal is connected to an electrode terminal of a battery. The detection terminal has an insertion hole into which a bolt is inserted. Due to the bolt being screwed into a screw hole formed in the electrode terminal with the detection terminal overlaid on the electrode terminal, the detection terminal and the electrode terminal are fastened and are thus electrically connected.